(1) Field of the Invention
The present invention relates generally to an electrical junction box, and, in particular, to an electrical junction box which has a primary housing and a secondary housing and is obtained by accommodating a circuit board assembly and other components inside of the primary housing, and then inserting the secondary housing into the primary housing.
(2) Description of the Related Art
A conventional electrical junction box is illustrated in FIGS. 6A and 6B. The electrical junction box 61 has a (a) low-profile primary housing 62, (b) a circuit board assembly 64, and (c) an upper cover 65 (i.e., the secondary housing).
The primary housing 64 has a low profile and is made of a synthetic resin. The circuit board assembly 64 is configured to be inserted in a vertical direction into the primary housing 62 via an opening 63 of the primary housing 62 so as to be accommodated thereinside. The opening 63 of the primary housing 62 opens on an upper side of the primary housing 62. The upper cover 65 is made of synthetic resin and configured to cover the opening 63 of the primary housing 62.
Terminals 68 are provided in two or more rows on an upper end of a circuit board 66. Also, terminals 69 are provided in two or more rows on a lower end of the circuit board 66. The terminals 68 extend upwardly while the terminals 69 extend downwardly.
Bodies 70 and 71 of a connector block are made of synthetic resin and adapted to align and secure the terminals 68 and 69, respectively. A plurality of relays (electrical components) 67 are found in an intermediate region of the circuit board 66.
Mounting members 73 are provided on an upper wall of the upper cover 65 adapted to allow the terminals 68 to protrude. Holes 74 are formed on a bottom wall 72 of the primary housing 62, likewise allowing the terminals 69 to protrude. A connector block 75 includes the terminals 68 and the body 70 while another connector block 76 includes the terminals 69 and the body 76. Each of electric fuses (not shown) is attached to the corresponding mounting member 73 and connected to the corresponding terminal 68 of the connector block 75. For details, refer to the description and, in particular, FIGS. 1 and 2 of Japanese Patent Application Laid-Open Publication No. 2003-348732.
The description and, in particular, FIGS. 1 to 3 of Japanese Patent Application Laid-Open Publication No. 2004-328842 discloses another type of the conventional electrical junction box (not shown). The electrical junction box of this type has the primary housing that is thinner and taller than that of the prior art shown in FIG. 6. This primary housing has openings on upper and bottom sides of the primary housing. Via these upper and lower openings, a bus bar circuit, an insulating plate, and terminals for electric fuse connection are mounted inside of the primary housing. The upper opening is covered by a fuse mounting part (i.e., the secondary housing) made of synthetic resin.
These existing electrical junction boxes need improvement. For instance, when the primary housing 62 made of synthetic resin is formed thin and tall so as to be mounted in a narrow space inside of an automobile, the wall of the primary housing 62 may warp inwardly. Such inward warpage of the wall of the primary housing 62 causes the opening 63 to be narrowed and restricted, making it difficult to mount the circuit board assembly 64, the secondary housing 65 and/or other components inside of the primary housing 62. In addition, when mounting the circuit board assembly 64, the wall of the primary housing 62 might be pressed inwardly from without. The inwardly pressed wall may interfere with the terminals 68, 69 and/or other components of the circuit board assembly 64 (e.g., the relay 67 and a resistor), in some cases deteriorating solder connection thereof. In particular, when the opening of the primary housing is only provided on either of the upper and lower walls thereof, insertion and/or mounting of the circuit board assembly inside of the primary housing is further deteriorated.